Everything new is old. The essential idea has been present in many forms actually. JSF, Seam, and others used standards based XML Markers that got rendered into

Everything new is old. The essential idea has been present in many forms actually. JSF, Seam, and others used standards based XML Markers that got rendered into other bits to accomplish essentially the same thing. HTMX doesn't use an XML schema, just a loose HTML convention, which is the big difference between the technologies. DWR (Direct Web Remoting)+jQuery was another form of the same thing.